JTAG port is what allows functional test, boundary scan and in-system programming of suitable ICs Check out http://www.asset-intertech.com/ which has a downloadable tutorial on the use of boundary scan Also http://www.jtag.com/ Nigel Burtt Production Engineering Manager D - European HQ Email: [log in to unmask] Tel: +44 (0)1793 842132 Fax:+44 (0)1793 842101 ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################